The text actually assumes that the four creatures are included with the
24 elders qualified by the word EKASTOS. The text also says that each
had *bowls* (plural), possibly meaning they each had at least two. Thus
(4x2)+(24x2)=56 bowls. However, I don't think there is any significance
in the number of the bowls or else John would have actually specified
the number. All John is content to say is that there are bowls amongst
these creatures and elders, and these represent the prayers of the
saints. Nothing more, nothing less. No numbers and numerology intended
here.